Systems and methods for thermal management for telecommunications enclosures using heat pipes

ABSTRACT

Systems and methods for thermal management for telecommunications enclosures are provided. In one embodiment, a method for thermal management for modular radio frequency (RF) electronics housed within an electronics enclosure comprises: distributing heat generated from an RF electronics component installed on a first thermal region of an electronics module base plate across the first thermal region using at least one primary heat pipe that laterally traverses the first thermal region; distributing heat generated from the RF electronics component to a second thermal region using at least one secondary heat pipe not parallel with the at least one primary heat pipe; conductively transferring heat across a thermal interface between the electronics module back-plate and a backplane of an electronics enclosure that houses the electronics module, wherein the backplane comprises a plurality heat sink fins aligned with the at least one primary heat pipe and the at least one secondary heat pipe.

BACKGROUND

Significant efforts are being made to increase thermal efficiency ofradio telecommunications equipment and reduce the amount of heatgenerated within the enclosures housing such equipment. However,dissipating heat generated by radio power amplifiers within thoseenclosure remains a problem for the wireless telecommunications industryfor at least two reasons. First, service providers are demanding moreand more compact equipment enclosures while at the same time expectinggreater functionality and capacity from each enclosure. Thus whilevarious innovations improve the thermal efficiency of individual poweramplifiers, the number of power amplifiers being housed in evershrinking enclosures is increasing. Second, in order to provide morecompact and less expensive equipment, the use of digital processingcircuitry is on the rise. Such digital processing circuitry is sensitiveto heat accumulation and will fail if operating temperatures within theequipment enclosure rise above their rated operating temperatures.

For the reasons stated above and for other reasons stated below whichwill become apparent to those skilled in the art upon reading andunderstanding the specification, there is a need in the art for improvedsystems and methods for thermal management for telecommunicationsenclosures.

SUMMARY

The Embodiments of the present invention provide methods and systems forthermal management for telecommunications enclosures and will beunderstood by reading and studying the following specification.

Systems and methods for thermal management for telecommunicationsenclosures are provided. In one embodiment, a method for thermalmanagement for modular radio frequency (RF) electronics housed within anelectronics enclosure comprises: distributing heat generated from an RFelectronics component installed on a first thermal region of anelectronics module base plate across the first thermal region using atleast one primary heat pipe that laterally traverses the first thermalregion; distributing heat generated from the RF electronics component toa second thermal region using at least one secondary heat pipe notparallel with the at least one primary heat pipe; conductivelytransferring heat across a thermal interface between the electronicsmodule back-plate and a backplane of an electronics enclosure thathouses the electronics module, wherein the backplane comprises aplurality heat sink fins aligned with the at least one primary heat pipeand the at least one secondary heat pipe.

DRAWINGS

Embodiments of the present invention can be more easily understood andfurther advantages and uses thereof more readily apparent, whenconsidered in view of the description of the preferred embodiments andthe following figures in which:

FIG. 1 is a simplified block diagram illustrating a removable radiofrequency (RF) electronics module of one embodiment of the presentinvention;

FIGS. 2A and 2B provide an isometric view of removable RF electronicsmodules in combination with an electronics enclosure, or one embodimentof the present invention; and

FIG. 3 is a flow chart illustrating a method of one embodiment of thepresent invention.

In accordance with common practice, the various described features arenot drawn to scale but are drawn to emphasize features relevant to thepresent invention. Reference characters denote like elements throughoutfigures and text.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof, and in which is shown byway of specific illustrative embodiments in which the invention may bepracticed. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it is tobe understood that other embodiments may be utilized and that logical,mechanical and electrical changes may be made without departing from thescope of the present invention. The following detailed description is,therefore, not to be taken in a limiting sense.

Embodiments of the present invention provide for thermal management oftelecommunications equipment enclosures through a strategic placement ofheat pipes that transfers heat from high temperature point sourceswithin removable RF electronics modules to non-heat saturated regions ofthe modules while at the same time orienting the heat pipes to spreadheat to a plurality of fins of the enclosures heat sink.

FIG. 1 is a simplified block diagram illustrating a removable radiofrequency (RF) electronics module 100 of one embodiment of the presentinvention. RF electronics module 100 comprises a base plate 110 having afirst thermal region 112 and a second thermal region 114. When installedinside an enclosure, the removable RF electronics module 100 as shown isoriented vertically such that the first thermal region 112 is positionedabove second thermal region 114 with respect to the Earth. Asillustrated in FIG. 1, RF electronic components 120 are mounted to thefirst region 112. In the second region 114, thermally sensitive digitalcomponents 122 are mounted. RF electronic components 120 includecomponents such as RF power amplifiers. In one embodiment, RF electroniccomponents 120 are laterally centered within first region 112. Digitalcomponents 122 include components such as, but are not limited to,microprocessor, digital signal processors, integrated circuits, datastorage buffers and or memories, and the like.

Within the first region 112, a plurality of linear heat pipes (shown at130) are positioned approximately parallel to each other and embeddedwithin base plate 110. Further, heat pipes 130 are oriented laterallyacross base plate 110 such that they traverse through an interfacingarea (shown at 116) of base plate 110 to which RF electronic components120 are mounted and conductively transfer heat to base plate 110.

In operation, heat pipes 130 conductively absorb heat from interfacingarea 116 and move that heat laterally outwards from interfacing area 116towards the edge regions 118 of base plate 110 within the first region112. In other words, heat pipes 130 function to draw at least some heataway from interfacing area 116 without drawing that heat towards thetemperature sensitive digital components 122 in the second region 114.

As would be appreciated by one of ordinary skill in the art upon readingthis specification, heat pipes do not themselves dissipate heat butinstead move heat from one location to another. Therefore, when too muchheat is moved from interfacing area 116 to edge regions 118, those edgeregions 118 will become heat saturated and unable to sink any more heat.

For this reason, at least one additional secondary heat pipe 132 isprovided within base plate 110 that is centered within interfacing area116 but curves down so that heat from components 120 is moved into thesecond region 114. In this case, secondary heat pipe 133 functions todraw heat away from interfacing area 116 toward regions 119, which arenot saturated with heat.

Heat pipe operation is based on gravity and capillary action. They workmost efficiently when the heat source is located at the lower end of theheat pipe and the heat sink region above. In that case, gravity forcesthe working fluid of the pipe down towards the heat source where itvaporizes and rises up towards the heat sink to cool. With the secondaryheat pipe 132 however, the heat source is located at interfacing area116, which is above the desired heat sink regions 119. Accordingly, thesecondary heat pipe 132 relies entirely on pumping provided by capillaryaction to bring the cooled working fluid back to interfacing area 116.This design therefore restricts the efficiency of secondary heat pipe132 so that some heat transfer from interfacing area 116 is provided,but without causing enough heat to accumulate in second region 114 tointerfere with the operation of digital components 122.

FIGS. 2A and 2B provides a more detailed isometric view of anelectronics enclosure 200 and removable RF electronics module 100installed onto a backplane 210 of the electronics enclosure 200.

As shown in FIG. 2A, in one embodiment, electronics enclosure 200comprises a top panel 217 and bottom panel 218 attached to a backplane210 and a pair of doors 215 each attached via respective hinges 216 tobackplane 210. When closed, doors 215, top panel 217, bottom panel 218and backplane 210 define a weather resistant environment for housing oneor more RF electronics modules (shown generally at 201) such as RFelectronics module 100. In the particular embodiment illustrated byFIGS. 2A and 2B, enclosure 200 is dimensioned to house up to four RFelectronics modules.

In one embodiment, either one or both of the panels 217, 218 includecable penetrations (shown generally at 219) to connect RF electronicsmodules 201 with external telecommunications equipment, networks, and/orpower sources. In operation, electronics enclosure 200 is approximatelyinstalled such that top panel 217 is oriented in an upward direction(that is, oriented away from the Earth) relative to bottom panel 218.Such an orientation of enclosure 200 is referred to herein as a“vertical” orientation.

Backplane 210 further functions as the primary heat sink for electronicsenclosure 200 and comprises a plurality of heat sink fins 220 (togetherwith those air spaces between the heat sink fins 220) that function toconvectively transfer heat generated within enclosure 200 to theexternal environment. Each of the RF electronics modules 201 includesone or more fastening systems 240 that secure RF electronics modules 201to backplane 210 such that a surface each module's base plate 110interfaces with an internal surface 212 of backplane 210. In oneembodiment, each module's base plate 110 thermally interfaces with theinternal surface 212 of backplane 210 via a thermally conducing pad(shown at 245) or similar material placed between the interfacingsurfaces of the RF electronics modules 201 and backplane 210. Each ofthe RF electronics modules 201 are secured within enclosure 200 suchthat their respective first thermal regions 112 are oriented towards toppanel 217 and their respective second thermal regions 114 are orientedtowards bottom panel 218. In one embodiment, as a results of RFelectronics module 100 installed as such, heat pipes 130 for each of theRF electronics modules are oriented to run substantially perpendicularto the heat sink fins 220 while secondary heat pipe 132 is oriented tocross over at least a plurality of the heat sink fins 220. Heat pipes130 and 132 will thus function to not only draw heat away from RFelectronic components 120 in a manner that avoids overheating of digitalcomponents 122, but also distribute that heat across backplane 210 forremoval into the environment external to enclosure 200.

FIG. 3 is a flow chart illustrating a method for thermal management formodular RF electronics within a telecommunications electronicsenclosure. The method begins at 310 with distributing heat generatedfrom an RF electronics component installed on a first thermal region ofan electronics module base plate across the first thermal region usingat least one primary heat pipe that laterally traverses the firstthermal region of the electronics module base plate. The method proceedsto 320 with distributing heat generated from the RF electronicscomponent to a second thermal region of the electronics module baseplate using at least one secondary heat pipe that is not parallel withthe at least one primary heat pipe. In one embodiment, one or moredigital components are mounted to the base plate within the secondthermal region, below the RF electronics components.

The method proceeds to 330 with conductively transferring heat across athermal interface between the electronics module back-plate and abackplane of an electronics enclosure that houses the electronicsmodule, wherein the backplane of the electronics enclosure comprises aplurality heat sink fins aligned with the at least one primary heat pipeand the at least one secondary heat pipe. In one embodiment, theelectronics module base plate is secured to the backplane of theelectronics enclosure with one or more fasteners that orient theelectronics module base plate such that the first thermal region ispositioned vertically above the second thermal region. In oneembodiment, heat is conductively transferring heat across the thermalinterface via a thermally conducing pad, a thermally conducting paste,or similar material placed between the interfacing surfaces of theelectronics module back-plate the backplane of the electronicsenclosure.

In one embodiment, as a result of the electronics module base plateinstalled as such, the primary heat pipes for each of the electronicsmodules installed within the enclosure are oriented to run substantiallyperpendicular to the heat sink fins while the secondary heat pipe isoriented to cross over at least a plurality of the heat sink fins. Theprimary and secondary heat pipes will thus function to not only drawheat away from the RF electronic components in a manner that avoidsoverheating of any digital components within the module, but alsodistribute that heat across the backplane of the enclosure for removalinto the external environment.

For the embodiments described above, the modular nature of havingremovable RF electronics modules that include the heat pipes (ratherthan, or in addition to including heat pipes with backplane, forexample) provides for flexibility in configuring combinations ofdifferent RF electronics modules within the enclosures. That is, theparticular position, orientation and number of heat pipes used for aparticular RF electronics module would be based on the particular designconsiderations for that module. However, each module would thermallyinterface with the enclosure in the same manner. Thus, with embodimentsof the present invention, a module having a first heat pipeconfiguration could easily be replaced within the enclosure by a modulehaving a different heat pipe configuration, without any need tostructurally alter the enclosure itself Where an enclosure includes aplurality of RF electronics modules, the heat pipe configurations withinthe base plate of each of those RF electronics modules need not be thesame.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement, which is calculated to achieve the same purpose,may be substituted for the specific embodiment shown. This applicationis intended to cover any adaptations or variations of the presentinvention. Therefore, it is manifestly intended that this invention belimited only by the claims and the equivalents thereof.

1. An thermal management system for radio frequency (RF) electronicshoused within an electronics enclosure, the system comprising: at leastone electronics module comprising a base plate having a first thermalregion and a second thermal region wherein one or more RF electroniccomponents are mounted to the first thermal region, wherein within thefirst thermal region, one or more primary heat pipes are laterallypositioned within the base plate to draw heat away from a region of thebase plate interfacing with the one or more RF electronic components andtowards edge regions of the base plate within the first region, the atleast on electronics module further comprising at least one secondaryheat pipe positioned within the base plate to draw heat away from theregion of the base plate interfacing with the one or more RF electroniccomponents into the second thermal region; an electronics enclosurecomprising a backplane, a top panel coupled to the backplane and abottom panel coupled to the backplane, the backplane comprising aplurality of heat sink fins that convectively transfer heat generatedwithin the electronics enclosure to an external environment; the atleast one electronics module further including one or more fasteningsystems that secure the electronics module to the base plate of theelectronics enclosure such that a surface of the base plate interfaceswith an internal surface the backplane, wherein the at least oneelectronics modules is secured within the electronics enclosure by theone or more fastening systems such that the first thermal region isoriented towards the top panel and the second thermal region is orientedtowards the bottom panel.
 2. The system of claim 1, wherein the baseplate thermally interfaces with the internal surface of the backplanevia a thermally conducing pad or a thermally conducting material.
 3. Thesystem of claim 1, wherein the one or more primary heat pipes areoriented to run substantially perpendicular to the heat sink fins whilethe at least one secondary heat pipe is oriented to cross over at leasta plurality of the heat sink fins.
 4. The system of claim 1, wherein theone or more primary heat pipes are oriented to run substantiallyperpendicular to the heat sink fins.
 5. The system of claim 1, whereinthe electronics enclosure is vertically oriented such that the top panelis oriented in an upward direction relative to the bottom panel.
 6. Thesystem of claim 1, wherein the second thermal region is positioned belowthe one or more RF electronics components.
 7. The system of claim 1,wherein the at least one secondary heat pipe is not parallel with theone or more are primary heat pipes.
 8. The system of claim 1, whereinthe one or more are primary heat pipes include a plurality of heat pipesthat are approximately parallel to each other.
 9. The system of claim 1,wherein the one or more RF electronic components include at least one RFpower amplifier.
 10. The system of claim 1, wherein the second regioncomprises one or more digital components mounted to the base plate. 11.The system of claim 10, Wherein the one or more digital componentscomprise one or more of a microprocessor, a digital signal processors,integrated circuits, a data storage buffer, or a memory.
 12. The systemof claim 1, the electronics enclosure further comprising doors eachattached to the backplane via hinges; wherein when the doors are closed,the doors, top panel, bottom panel and backplane form a weatherresistant environment for housing the at least one RF electronicsmodules.
 13. The system of claim 1, wherein the electronics enclosurehouses two electronics modules of the at least one electronics modules,the two electronics modules having heat pipe configurations that aredifferent from each other.
 14. A method for thermal management formodular radio frequency (RF) electronics housed within an electronicsenclosure, the method comprising: distributing heat generated from an RFelectronics component installed on a first thermal region of anelectronics module base plate across the first thermal region using atleast one primary heat pipe that laterally traverses the first thermalregion of the electronics module base plate; distributing heat generatedfrom the RF electronics component to a second thermal region of theelectronics module base plate using at least one secondary heat pipethat is not parallel with the at least one primary heat pipe;conductively transferring heat across a thermal interface between theelectronics module back-plate and a backplane of an electronicsenclosure that houses the electronics module, wherein the backplane ofthe electronics enclosure comprises a plurality heat sink fins alignedwith the at least one primary heat pipe and the at least one secondaryheat pipe.
 15. The method of claim 14, wherein one or more digitalcomponents are mounted to the base plate within the second thermalregion.
 16. The method of claim 14, wherein the electronics module baseplate is secured to the backplane of the electronics enclosure with oneor more fasteners that orient the electronics module base plate suchthat the first thermal region is positioned vertically above the secondthermal region.
 17. The method of claim 14, wherein heat is conductivelytransferring heat across the thermal interface via one or more of athermally conducing pad or a thermally conducting paste placed betweeninterfacing surfaces of the electronics module back-plate and thebackplane of the electronics enclosure.
 18. The method of claim 14,wherein the at least one primary heat pipe is oriented to runsubstantially perpendicular to the heat sink fins
 19. The method ofclaim 14, wherein at least one the secondary heat pipe is oriented tocross over at least a plurality of the heat sink fins.
 20. The method ofclaim 14, wherein the plurality of heat sink fins are orientedperpendicularly with respect to a orientation of the at least oneprimary heat pipe.